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01-07-2015, 06:38 PM   #1
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USB power input on a DSLR or mirrorless?

So this started in another thread, but I think giving it it's own thread is much more appropriate.


QuoteOriginally posted by kadajawi Quote
Btw., am I the only one who wants a USB power input in my camera? i.e. being able to charge the battery via USB, especially while using the camera. Imagine shooting star trails at night... the battery dies. Changing it ruins the picture. But if you can simply keep the camera running via external USB battery? Even if that dies, the internal battery will be charged enough for you to switch the external battery without interruption. I am already really enjoying the external battery charger that can take USB power sources...
QuoteOriginally posted by BrianR Quote
Some models have a "DC in" slot that you can hook an external battery up to, DIY Power Supply for Pentax K5 DSLR . I think the USB voltage is too low to power the camera, but some of the portable chargers also have higher voltage DC out ports, like this one. I'm not sure if there's an 'off the shelf' option for pentax though.
QuoteOriginally posted by kadajawi Quote
The DC input is not nearly as convenient as a USB input. And while the camera may sometimes need more power, the USB input would be used to charge the battery consistently. The camera itself runs off the internal battery.

I also have a two port USB charger, and there are some with 4 and more. When traveling you just need to bring one of those, no small charger you can loose, and you can charge the camera and your phone, tablet, ...

Or you just charge your camera at the end of the day by plugging it into the computer... And at the same time the files are transferred.

As an additional bit of convenience it would be great.

QuoteOriginally posted by philbaum Quote
There's another reason to going to USB charging. In countries that don't have an infrastructure of high AC voltage lines and step down power stations, small villages and apartment buildings are installing solar panels and a DC network using USB type connectors. I read an article about a year ago that reported existing USB connectors are designed for 5 watts, IIRC, but a new design for a 100 watt USB connector is being developed. So worldwide, it appears that USB connectors will allow more future interconnectivity than any other design. My half-assed opinion only :-)
QuoteOriginally posted by Ex Finn. Quote
I would hate to have to deal with a USB cable that can carry 20 amps...
It must be something completely different from the current standard.
QuoteOriginally posted by devorama Quote
Yes, they would require USB Power Delivery compliant cables. The 100W max would be 20V @ 5A. The power sources would default to 5V and then increase based upon negotiation with the device. My Samsung Note4 has a fast charging mode that increases the voltage to 9V for a faster recharge.
QuoteOriginally posted by kadajawi Quote
It's not like our regular chargers need so much power anyway. But I'll start a new thread for this...
So... yeah. I believe Samsung gave the NX1 that capability, but forgot to include a regular charger (1500 Euro for a camera, and it doesn't come with a charger. What the ...? It's optional. And I think someone complained you can't use the camera while charging the battery in the camera... if that's true...). I would like to see that capability as an extra to the regular way of charging. That way we could also, if we bring along the regular charger (which should also have a USB input!) charge 2 batteries at the same time.


A regular 2.1A/5V input should be enough. The K-5 adapter has 8.4V and 2A, which is a bit more, but since the battery acts as a buffer I don't think it's so much of an issue when the camera temporarily draws more power. 8.4V and 2A seem to be worst case scenario... it's impossible for the camera to draw more than that.


Usage scenarios would be charging the camera on the go or keeping it alive. Chances are you already have a micro USB cable with you, as well as a charger. Or a USB battery pack. Cars these days come with USB ports for charging your phone, and if not a 12V USB adapter is pretty cheap. If you are visiting someone, he'll probably have a USB charger for his phone anyway. And on, and on and on. No more "oh no, I've forgotten the charger at home and my battery is almost dead!" It's basically the good old AA battery, just more modern. You should be able to charge the battery anywhere.

01-07-2015, 07:20 PM   #2
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Wait for Wireless charging
01-07-2015, 07:24 PM   #3
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QuoteOriginally posted by Steve.Ledger Quote
Wait for Wireless charging
I don't want that. It needs to be placed perfectly on the mat, it's not cheap, not so fast, ... plugging in a cable is not THAT hard.
01-07-2015, 08:36 PM   #4
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You cannot charge a battery using less voltage than the battery is rated for. I seriously doubt if it would even prolong the charge of the battery. USB voltage is 5 VDC. Most if not all DSLR use more than 5 VDC to operate.

01-07-2015, 08:54 PM   #5
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QuoteOriginally posted by kadajawi Quote
I don't want that. It needs to be placed perfectly on the mat, it's not cheap, not so fast, ... plugging in a cable is not THAT hard.
Which is why I used the word 'wait'.. I know it's not viable yet, but like most new [and cool tech] things - they improve.
01-08-2015, 04:24 AM   #6
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Actually it isn't impossible to charge from USB. I'm playing idea and working on charger which would charge slowly (input current less than 100mA) or faster (input voltage stays above 4.5V) step-up switcher and on the other end there would be 2 cell li-ion chaging possibility Also to the other direction. From D-li90 to USB charge.

Putting that kind of circuit inside camera would be difficult, not impossible, task. High efficiency, electrical, rf and audio noise from my prototype make things interesting.
01-08-2015, 06:35 AM   #7
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QuoteOriginally posted by kkoether Quote
You cannot charge a battery using less voltage than the battery is rated for. I seriously doubt if it would even prolong the charge of the battery. USB voltage is 5 VDC. Most if not all DSLR use more than 5 VDC to operate.
Ladeger


That's what I have. It can use USB, I use it all the time to charge my K-5 battery via USB.
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